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Vanguard (6.5in)

Vanguard 1 was a small earth-orbiting satellite designed to test the launch
capabilities of a three-stage launch vehicle and the effects of the environment on a
satellite and its systems in Earth orbit. It also was used to obtain geodetic measurements
through orbit analysis.

The spacecraft was a 1.47 kg aluminum sphere 15.2 cm in diameter. It contained a 10-mW,
108 MHz mercury-battery powered transmitter and a 5-mW, 108.03 MHz transmitter powered by
six solar cells mounted on the body of the satellite. Six short aerials protruded from the
sphere. The transmitters were used primarily for engineering and tracking data, but were
also used to determine the total electron content between the satellite and ground
stations. Vanguard also carried two thermistors which measured the interior temperature
over 16 days in order to track the effectiveness of the thermal protection.

Vanguard TV3 was the first U.S. attempt to launch a satellite into orbit around the
Earth. It was a small satellite designed to test the launch capabilities of a three-stage
launch vehicle and study the effects of the environment on a satellite and its systems in
Earth orbit. It also was to be used to obtain geodetic measurements through orbit
analysis.

At launch the booster ignited and began to rise but about 2 seconds after liftoff,
after rising about four feet, the Vanguard
rocket lost thrust and began to settle back down to the launch pad. As it settled against
the launch pad the fuel tanks ruptured and exploded, destroying the rocket and severely
damaging the launch pad. The Vanguard satellite was thrown clear and landed on the ground
a short distance away with its transmitters still sending out a beacon signal. The
satellite was damaged, however, and could not be reused. It is now on display at the
Smithsonian Air and Space Museum. The exact cause of the accident was never determined,
presumably it was due to a fuel leak between the fuel tank and the rocket engine, possibly
due to a loose connection in a fuel line or low fuel tank pressure allowing some of the
burning fuel in the thrust chamber to leak back into the fuel tank.

Vanguard TV3BU failed also to reach orbit.

Vanguard 1 was placed into a 654 × 3969 km 134.2 minute orbit inclined at 34.25 degrees
by the three stage Vanguard launch vehicle.
Original estimates had the orbit lasting for 2000 years, but it was discovered that solar
radiation pressure and atmospheric drag during high levels of solar activity produced
significant perturbations in the perigee height of the satellite, which caused a
significant decrease in its expected lifetime to only about 240 years. The battery powered
transmitter stopped operating in June 1958 when the batteries ran down. The solar powered
transmitter operated until May 1964 (when the last signals were received in Quito,
Ecuador) after which the spacecraft was optically tracked from Earth.

An additional flight back up is now on display in the Space Science exhibition station at the Steven F. Udvar-Hazy Center in Chantilly, VA.